In the field of radio communication, especially in mobile communication, a variety of information such as image and data in addition to voice has become an object of transmission in recent years. The demand for higher-speed transmission is expected to further increase in the future, and, to perform high-speed transmission, a radio transmission technology is required that utilizes limited frequency resources more effectively and achieves high transmission efficiency.
OFDM (Orthogonal Frequency Division Multiplexing) is one of radio transmission techniques to meet the demand (e.g. see Non-Patent Document 1). It is known that OFDM features high frequency efficiency and low inter-symbol interference under a multipath environment and is effective to improve transmission efficiency. Particularly, in OFDM, the frequencies of a plurality of subcarriers where data is mapped are orthogonal to each other, so that it is possible to achieve best frequency efficiency in multicarrier communications and OFDM can be realized multicarrier communication in a relatively simple hardware configuration. For this reason, OFDM is attracted attention as a communication method to be employed in mobile communications, and is studied variously.
Non-Patent Document 1: WS No. 197, “OFDM modulation technology for digital broadcast/mobile communication,” published by Triceps Corporation, on Mar. 7, 2000